SE542005C2

SE542005C2 - A multi-purpose end plug

Info

Publication number: SE542005C2
Application number: SE1730280A
Authority: SE
Inventors: Olof Thylén
Original assignee: Distex Byggsystem Ab
Priority date: 2017-10-06
Filing date: 2017-10-06
Publication date: 2020-02-11
Also published as: SE1730280A1

Abstract

:An end plug (1) for use in hollow concrete panels (2), said end plug (1) having a first wall section (11) and a second circumambient wall section (12). The second circumambient wall section (12) is connected to a circumference of the first wall section (11) at a first end (12), The second circumambient wall section (12) have an opposite end (12). The second circumambient wall section (12) together with the first wall section (11) describes a mainly rotary symmetrical object. A diameter at the opposite end (12) is larger than a diameter at the first end (12). The first wall section (11) is provided with at least one slot (13) arranged adjacent to the first end (12). The at least one slot (13) provides means for deflection of the second circumambient wall section (12) and at the same time allow air and moisture to pass.

Description

A multi-purpose end plug.

BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to a novel and improved multi-purpose end plug for use in building construction. 2. Description of related prior art Hollow prefabricated concrete panels have been used for decades. These hollow concrete panels are foremost used as floor sections and are designed to carry large loads. The hollow profile design will increase their capacity for carrying large amounts of loads while keeping the weight down. The hollow concrete panels have many uses, but as example can be mentioned; floor sections in apartment and office buildings, bridges, factory construction, parking garages and sports & entertainment arenas.

The hollow concrete panels are normally manufactured through extrusion or casting far away from the construction site. The hollow concrete panels often have standardized dimension and can accordingly, to some extent, be seen as an "off the shelf product". These hollow concrete panels will need to cure for days and are often stored outdoors for extended periods of time.

It is important to make sure that, for example snow or autumn leaves does not collect inside the hollow profiles. It has also been known that animals nest, dwell or choose these holes for winter hibernation. It is therefore common practice to utilise a special purpose plug to seal off these holes. These plugs need to be designed in such a way that ventilation is allowed in order to allow the concrete to dry out after curing as well as after rain or melting snow.

One specific problem, which so far has not been addressed, is connected to the assembly, i.e. when the building is constructed. A number of hollow concrete panels will be arranged on top of wall-sections, beams and/or pillars. The hollow concrete panels will very often also be arranged adjacent to one another so that the holes meet over the joint. The hollow concrete panels are predominantly secured to the construction by pouring concrete into the joint. This concrete needs to be of a low viscosity to secure that it fills the voids in the joint and leaves a solid, sturdy and secure joint. Here a problem occurs that the concrete used for the joint will also flow a significant distance into the holes in the hollow concrete panels. This will increase the weight of the building construction to such an extent that the weight increase needs to be taken into consideration when calculating dimensions of the load carrying parts of the construction. These collected problems have not yet been solved without great extra efforts and laborious solutions. It is known that the holes in the hollow concrete panels forms channels which sometimes are used for ventilation and sometimes even electrical and communication installations. These desires will further increase the labour intensity and therefore increase building costs.

Known special purpose plugs will often fail in cases where a type of joint identified as K-joint is used. In this type of joint, plugs are not supported at its upper end and may hence fall into the channel under the weight of the concrete poured into the joint. Large amounts of this concrete may then enter the channels. It is also known that plugs may fall off, for example during transportation or handling. Missing plugs could of course be replaced before lifting the hollow concrete panels into position. This is however not likely since it becomes an extra moment in the construction workers routine that is easily overlooked.

SUMMARY OF THE INVENTION It has through the present invention been made possible to solve the above mentioned problems and at the same time offer a more economical and flexible manner of operation.

Accordingly, the present invention relates to an end plug for use in hollow concrete panels. The invention is characterised in that said end plug have a first wall section and a second circumambient wall section. The second circumambient wall section is connected to a circumference of the first wall section at a first end. The second circumambient wall section have an opposite end. The second circumambient wall section together with the first wall section describes a mainly rotary symmetrical object. A diameter at the opposite end is larger than a diameter at the first end. The first wall section is provided with at least one slot arranged adjacent to the first end. Said at least one slot provides means for deflection of the second circumambient wall section and at the same time allow air and moisture to pass.

According to a preferred embodiment of the invention the first wall section is provided with at least two slots. A connection point is arranged between two adjacent slots. The connection point is irremovably connecting the first wall section and the second circumambient wall section. The number of slots and connection points are the same.

A collected connection point area is preferably smaller than the area made up by slots.

According to a preferred embodiment of the invention, the first wall section is mainly semi-spherical, parabolic or similarly bulged with the convex surface facing the same direction as the second circumambient wall section.

The second circumambient wall section is suitably provided with an inwards directed lip at the first end and where slots are located. This will make the area of the slot narrower when concrete is pressing on the first wall section, hereby minimizing the risk that the concrete enters the hollow concrete panels during joining of two adjacent panels. This is highly advantageous.

According to a special embodiment of the invention the first wall section is provided with a knock out section. The knock out section is made up by a series of holes arranged in a circle, square or other suitable geometric shape. The knock out section provides means for arranging installations selected from the group consisting of; ventilation ducts, electrical power cables, signal cables, fibre optics and a combination thereof inside the hollow concrete panels once the knock out section is removed.

There are several different ways of joining hollow concrete panels in the construction industry. One such way is the so called K-joint, where a cut-out is formed in the upper face of the hollow concrete panel. This cut-out will allow reinforcement bars to be arranged in the joint. The larger opening of the joint will also ensure that the concrete used for joining reaches all the way down to the underlying wall, beam or pillar.

In this type of joint, according to a preferred embodiment of the invention the end plug have a second circumambient wall section which protrudes further from the first wall section at a lower portion of the circumference.

The lower portion may further be provided with a series of narrow longitudinal slits. The purpose of these slits is to allow the concrete used for joining to have some contact with the lower portion of the channels in the hollow concrete panel. This will add some strength to the joint.

The end plug is preferably injection moulded from a semi-flexible thermoplastic material selected from the group consisting of; low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene and polyvinyl chloride. The goods thickness of the second circumambient wall section is < 3mm, preferably < 2mm to allow flexibility. An outer surface of the second circumambient wall section is suitably further free from reinforcing ribs, girders and the like. A certain amount of flexibility is desired as the hollow channels in the concrete panels are not always perfectly circular and are not always of exactly the same dimension from one batch to another. It is therefore important that the end plug is flexible enough to account for these variations. It is of course possible to use a plasticizer in the thermoplastic material in order to achieve the desired flexibility. However, some of the above mentioned materials will be flexible enough if goods thickness is reduced. This will then provide the benefit of material savings, shorter cycle times in the injection moulding process which together will make the product more cost effective.

DESCRIPTION OF AN EMBODIMENT EXAMPLE The invention is further described together with enclosed drawings showing a selected embodiment of the invention, wherein, -figure 1 show, in cross section, a portion of a first type of joint where an end plug 1 according to the invention is used. -figure 2 show, in cross section, a portion of a second type of joint where an end plug 1 according to the invention is used. -figure 3 show, in cross section, a portion of a joint according to prior art. -figure 4a and 4b show, in perspective view and in cross section respectively, a first embodiment of an end plug 1 according to the invention. -figure 5 show, in perspective view, a second embodiment of an end plug 1 according to the invention.

Accordingly, figure 1 show, in cross section, a portion of a first type of joint between two hollow concrete panels 2. An end plug 1 of the present invention is installed at the end of each of the two hollow concrete panels 2, which then has been arranged on top of a carrying beam 3. Joint concrete 4 has then been poured into the gap formed between the two hollow concrete panels 2. The end plugs 1, are effectively stopping the joint concrete 4 from entering the channels of the hollow concrete panels 2.

Figure 2 show, in cross section, a portion of a second type of joint between two hollow concrete panels 2. This type of joint is known in the industry as a K-joint. An end plug 1 of the present invention is installed at the end of each of the two hollow concrete panels 2, which then has been arranged on top of a carrying beam 3. The end plug 1 is further provided with a second circumambient wall section 12 which protrudes further at a lower portion 12L- Joint concrete 4 has then been poured into the gap formed between the two hollow concrete panels 2. The end plugs 1 , are effectively stopping the joint concrete 4 from entering the channels of the hollow concrete panels 2. The end plug 1 is further provided with a knock out section 16 allowing for example ventilation ducts to be arranged inside the hollow concrete panels 2. A circular block of Styrofoam or a tube of any suitable material is suitable inserted in holes created once the knock out section is removed, prior to adding the joint concrete 4. The latter is, for the sake of simplicity, not shown the figure.

Figure 3 show, in cross section, a portion of a joint in accordance to prior art. Two adjacent hollow concrete panels 2 have been capped with a known end cap 50. The end cap 50 is made up by a series of ribs holding a central plate in position. The prior art end cap 50 will hinder animals from entering the hollow concrete panels 2 and also, to some extent, hinder autumn leaves from collecting inside the channels. They will however not hinder rain to enter the channels during storage nor will it stop joint concrete 4 from entering said channels. Known end caps 50 are also known to often fail in cases where the type of joint identified as K-joint in the industry is used. In this type of joint, end caps 50 are not sufficiently supported at its upper end and too often fall into the channel under the weight of the joint concrete 4 poured into the joint. Large amounts of this concrete may then enter the channels. As there so far has not been a secure solution to this problem, the building construction has to be dimensioned to handle the possibility of the extra weight which makes the building more expensive. Known end caps 50 are also known to fall off during transportation and handling. A missing end cap 50 will of course allow undesired free flow of joint concrete 4 into the channels.

Figure 4a shows in perspective view, an end plug 1 according to a first embodiment of the invention. See also cross section view in figure 4b. The end plug 1 have a first wall section 11 and a second circumambient wall section 12. The second circumambient wall section 12 is connected to a circumference of the first wall section 11 at a first end 12. The second circumambient wall section 12 have an opposite end 12. The second circumambient wall section 12 together with the first wall section 11 describes a mainly rotary symmetrical object. A diameter at the opposite end 12is larger than a diameter at the first end 12. The first wall section 11 is provided with an upper and a lower slot 13 arranged adjacent to the first end 12. These slots 13 provides means for deflection of the second circumambient wall section 12 and at the same time allow air and moisture to pass during curing and storage.

Connection points 14 are arranged between the two slots 13. The first wall section 11 is mainly semi-spherical with the convex surface facing the same direction as the second circumambient wall section 12.

As best seen in cross section in figure 4b, the second circumambient wall section 12 is provided with an inwards directed lip 15 at the first end 12and where slots 13 are located. This lip 15 will provide two features. The first feature is that it will reinforce the section so that the weight of the joint concrete 4 ( see figure 1 and 2) will not deflect the wall of the first end 12downwards to any noticeable extent. Secondly, the weight of the joint concrete 4 (see figure 1 and 2) will deflect the lower portion of the first wall section towards the lip 15 and will make the slot 13 smaller so that the joint concrete 4 (see figure 1 and 2) cannot enter the channels of the hollow concrete panels 2.

As best seen in figure 5 the first wall section 11 is according to a special embodiment of the invention provided with a knock out section 16. The knock out section is made up by a series of holes 17 arranged in a circle as depicted. Other shapes like square or other suitable geometric shape is of course possible within the scope of the invention.

As best seen in figure 5 the second circumambient wall section 12 protrudes further from the first wall section 11 at a lower portion 12Lof the circumference. This embodiment of the present invention is the preferred embodiment to utilize in so called K-joints shown in figure 2. The lower portion 12Lis optionally provided with a series of narrow longitudinal slits.

The invention is not limited by the embodiments shown since these can be varied in different ways within the scope of the invention. The knock out section 16 may for example be omitted in the embodiment shown in figure 5, -so may the longitudinal slits be. A knock out section 16 may also be used on the embodiment shown in figure 4, -so may the longitudinal slits be.

Claims

WE CLAIM

1. An end plug (1) for use in hollow concrete panels (2), characterised in that said end plug (1) have a first wall section (11) and a second circumambient wall section (12), said second circumambient wall section (12) being connected to a circumference of the first wall section (11) at a first end (12), that the second circumambient wall section (12) have an opposite end (12), the second circumambient wall section (12) together with the first wall section (11) describing a mainly rotary symmetrical object, that a diameter at the opposite end (12) is larger than a diameter at the first end (12), and that the first wall section (11) is provided with at least one slot (13) arranged adjacent to the first end (12), said at least one slot (13) providing means for deflection of the second circumambient wall section (12) and at the same time allow air and moisture to pass, that the first wall section (11) is mainly semispherical, parabolic or similarly bulged with the convex surface facing the same direction as the second circumambient wall section (12), and that the second circumambient wall section (12) is provided with an inwards directed lip (15) at the first end (12) and where slots (13) are located.

2. An end plug (1) according to claim 1, characterised in that the first wall section (11) is provided with at least two slots (13), that a connection point (14) is arranged between two adjacent slots (13), the connection point (14) is irremovably connecting the first wall section (11) and the second circumambient wall section (12), and that the number of slots (13) and connection points (14) are the same.

3. An end plug (1) according to claim 2, characterised in that a collected connection point (14) area is smaller than the area made up by slots (13).

4. An end plug (1) according to any of the claims 1 - 3, characterised in that the first wall section (11) is provided with a knock out section (16), said knock out section being made up by a series of holes (17) arranged in a circle, square or other suitable geometric shape, said knock out section (16) providing means for arranging installations selected from the group consisting of; ventilation ducts, electrical power cables, signal cables, fibre optics and a combination thereof inside the hollow concrete panels (2) once the knock out section (16) is removed.

5. An end plug (1) according to any of the claims 1 - 4, characterised in that the second circumambient wall section (12) protrudes further from the first wall section (11) at a lower portion (12L) of the circumference.

6. An end plug (1) according to claim 5, characterised in that the lower portion (12L) is provided with a series of narrow longitudinal slits.

7. An end plug (1) according to any of the claims 1 - 6, characterised in that the end plug is injection moulded from a semi-flexible thermoplastic material selected from the group consisting of; low density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene and polyvinyl chloride. An end plug (1) according to claim 7, characterised in that the goods thickness of the second circumambient wall section (12) is <3mm, preferably <2mm to allow flexibility, that an outer surface of the second circumambient wall section (12) is free from reinforcing ribs, girders and the like.